Medical thoracoscopy has an important place in the diagnosis and management of pleural disease. However, the application of this procedure is limited in the United Kingdom. This may be partly because respiratory physicians remain unfamiliar with standard rigid thoracoscopy instruments. However, the semirigid variant, popular in Europe and Japan, is similar in design to the commonly used flexible bronchoscope. The larger biopsy size obtained with the conventional rigid thoracoscope has been quoted as a reason for its superiority. To compare the histologic yield of the 2 instruments, the current authors studied a series of 66 patients with unilateral exudative pleural effusions. Twenty-seven rigid and 39 semirigid thoracoscopy procedures were included. Thoracoscopic pleural biopsy achieved a positive diagnosis in 26 of 27 patients in the rigid thoracoscopy group (96.3%) and 36 of 39 patients in the semirigid group (92.3%). Statistically, this difference was not significant (95% confidence intervals, -0.11 to 0.17). Our study demonstrates that the semirigid thoracoscope achieves a diagnostic yield similar to that of the conventional rigid instrument despite the smaller biopsy size. Both instruments remain valuable in the evaluation and management of pleural disease.